FAQ About Luis Walter Alvarez

In 1980, Luis Alvarez, along with his son Walter Alvarez, proposed the asteroid impact hypothesis. This theory suggests that the mass extinction event that wiped out the dinosaurs 66 million years ago was caused by the impact of a large asteroid or comet. The hypothesis was supported by the discovery of a worldwide layer of sediment rich in iridium, a metal more common in asteroids than in the Earth's crust.